1. Field of the Invention
The present invention relates to a novel organotin compound; which can work as a catalyst for transesterification. More specifically, the present invention relates to a catalyst for transesterification which enables for the highly efficient preparation of an ester compound in a high purity under less restrictive conditions.
2. Background Art
Hitherto, organic compounds such as dialkyltin oxide, dialkyltin dicarboxylate, and hydroxymonoalkyltin oxide are widely utilized as effective catalysts for transesterification. For example, preparation of perfluoroalkyl methacrylate by means of transesterification of perfluoroalcohol and methyl methacrylate is disclosed in U.S. Pat. No. 4,360,670, and formation of aromatic dicarboxylic acid diphenyl ester from aromatic dicarboxylic acid and phenyl acetate is described in JP-A-58-213734. An organotin compound could also work as a catalyst in providing diphenyl carbonate from dimethyl carbonate and phenol disclosed in JP-A-8-188558.
However, these organotin compounds described above have low activity for transesterification, and hence, the use of those compounds and the strict reaction conditions, e.g., high reaction temperature, are required in order to achieve a high conversion. In addition, their optical activity is easily lost in the transesterification using a substrate bearing an optically active group. Namely, conventional organotin compounds do not impart a sufficiently high catalytic activity, and many problems have arose in performing reactions with optically active substrates using these catalysts.